<html>
  <head>
    <!-- Disable extra network request for /favicon.ico -->
    <link rel="icon" href="data:,">

    <script>
      // Navigates a child of the opener window to the given url.
      //
      // `url` is where the child should be navigated to.
      window.addEventListener("message", (event) => {
        const { url, initiatorBehavior } = event.data;
        window.opener.mainChild.contentWindow.location = url;
        if (initiatorBehavior == "close") {
          window.close();
        } else if (initiatorBehavior == "navigate") {
          window.location = "about:blank";
        }
      });
    </script>
  </head>
  <body></body>
</html>
